Space charge breakdown in PMMA without applied field

Space charge was introduced into polymethyl methacrylate (PMMA) by electron beam radiation and the interactional mechanism between space charge and PMMA was investigated in this paper. A new model of space charge effect breakdown, based on the traditional dielectric treeing breakdown theory, was promoted. This model proposes that dielectric space charge breakdown doesn´t always occur during injection or acceleration of space charge under applied field, the breakdown can also be generated during detrapping of space charge, and applied field is not a necessary condition for dielectric breakdown.